People going from cable modem -> ROUTER -> computer -> xbox...
I could not get this setup to work. I changed my setup to
cable modem -> router -> computer AND
cable modem -> router -> xbox
Not sure of the problem with the first setup. Maybe some of my dns, gateway, IPs were wrong or cross cable not working. But switched cross over to regular and hooked up xbox to router and everything good to go!
Hope this helps anyone else having this problem.